diff --git a/v6d3music/core/entries_effects_for_args.py b/v6d3music/core/entries_effects_for_args.py
index b669674..9da95af 100644
--- a/v6d3music/core/entries_effects_for_args.py
+++ b/v6d3music/core/entries_effects_for_args.py
@@ -8,6 +8,9 @@ from v6d3music.config import myroot
 from v6d3music.utils.presets import allowed_effects
 
 
+__all__ = ('effects_db', 'default_effects', 'set_default_effects', 'entries_effects_for_args',)
+
+
 effects_db = Db(myroot / 'effects.db', kvfactory=KVJson())
 
 
@@ -26,6 +29,6 @@ async def set_default_effects(gid: int, effects: str | None) -> None:
 
 
 async def entries_effects_for_args(args: list[str], gid: int) -> AsyncIterable[InfoCtx]:
-    for ctx in ArgCtx(default_effects, args, gid).sources:
+    for ctx in ArgCtx(default_effects(gid), args).sources:
         async for it in ctx.entries():
             yield it
diff --git a/v6d3music/core/ystate.py b/v6d3music/core/ystate.py
new file mode 100644
index 0000000..9d79288
--- /dev/null
+++ b/v6d3music/core/ystate.py
@@ -0,0 +1,117 @@
+import asyncio
+from collections import deque
+from contextlib import AsyncExitStack
+from typing import AsyncIterable, Iterable
+
+from v6d3music.core.create_ytaudio import *
+from v6d3music.core.ytaudio import *
+from v6d3music.processing.pool import *
+from v6d3music.utils.argctx import *
+
+from v6d2ctx.context import Context
+
+__all__ = ('YState',)
+
+
+class YState:
+    def __init__(self, pool: Pool, ctx: Context, sources: Iterable[UrlCtx]) -> None:
+        self.pool = pool
+        self.ctx = ctx
+        self.sources: deque[UrlCtx] = deque(sources)
+        self.playlists: deque[asyncio.Future[list[InfoCtx]]] = deque()
+        self.entries: deque[InfoCtx | BaseException] = deque()
+        self.results: asyncio.Queue[asyncio.Future[YTAudio | None] | None] = asyncio.Queue()
+        self.es = AsyncExitStack()
+        self.descheduled: int = 0
+
+    def empty(self) -> bool:
+        return self.empty_processing() and self.results.empty()
+
+    def empty_processing(self) -> bool:
+        return not self.sources and not self.playlists and not self.entries
+
+    async def iterate(self) -> AsyncIterable[YTAudio]:
+        async with self.es:
+            for _ in range(self.pool.workers()):
+                await self.es.enter_async_context(YJD(self).at(self.pool))
+            while not self.empty():
+                future = await self.results.get()
+                if future is None:
+                    return
+                try:
+                    audio = await future
+                    if audio is not None:
+                        yield audio
+                except OSError:
+                    raise Explicit('extraction error\nunknown ytdl error')
+                finally:
+                    self.results.task_done()
+
+    async def playlist(self, source: UrlCtx) -> list[InfoCtx]:
+        return [info async for info in source.entries()]
+
+    async def result(self, entry: InfoCtx) -> YTAudio | None:
+        try:
+            return await create_ytaudio(self.ctx, entry)
+        except:
+            if not entry.ignore:
+                raise
+            else:
+                return None
+
+
+class YJD(JobDescriptor):
+    def __init__(self, state: YState) -> None:
+        self.state = state
+
+    def _unpack_playlists(self) -> None:
+        while self.state.playlists and self.state.playlists[0].done():
+            playlist = self.state.playlists.popleft()
+            if (e := playlist.exception()) is not None:
+                self.state.playlists.clear()
+                self.state.sources.clear()
+                self.state.entries.append(e)
+            else:
+                for entry in playlist.result():
+                    self.state.entries.append(entry)
+
+    async def run(self) -> JobDescriptor | None:
+        if self.state.empty_processing():
+            if self.state.results.empty():
+                self.state.results.put_nowait(None)
+            return None
+        elif self.state.entries:
+            entry = self.state.entries.popleft()
+            audiotask: asyncio.Future[YTAudio | None]
+            if isinstance(entry, BaseException):
+                audiotask = asyncio.Future()
+                audiotask.set_exception(entry)
+            else:
+                audiotask = asyncio.create_task(self.state.result(entry))
+            self.state.results.put_nowait(audiotask)
+            try:
+                await audiotask
+            except:
+                self.state.entries.clear()
+                self.state.playlists.clear()
+                self.state.sources.clear()
+            return self
+        elif self.state.sources:
+            source = self.state.sources.popleft()
+            playlisttask = asyncio.create_task(self.state.playlist(source))
+            self.state.playlists.append(playlisttask)
+            try:
+                await playlisttask
+            except:
+                self.state.sources.clear()
+                return self
+            finally:
+                self._unpack_playlists()
+            rescheduled = self.state.descheduled
+            self.state.descheduled = 0
+            for _ in range(rescheduled):
+                await self.state.es.enter_async_context(YJD(self.state).at(self.state.pool))
+            return self
+        else:
+            self.state.descheduled += 1
+            return None
diff --git a/v6d3music/core/yt_audios.py b/v6d3music/core/yt_audios.py
index 8f01b81..30405e0 100644
--- a/v6d3music/core/yt_audios.py
+++ b/v6d3music/core/yt_audios.py
@@ -1,21 +1,17 @@
 from typing import AsyncIterable
 
-from v6d3music.core.create_ytaudios import create_ytaudios
-from v6d3music.core.entries_effects_for_args import entries_effects_for_args
+from v6d3music.core.entries_effects_for_args import *
+from v6d3music.core.ystate import *
 from v6d3music.core.ytaudio import YTAudio
-from v6d3music.utils.argctx import InfoCtx
+from v6d3music.processing.pool import *
+from v6d3music.utils.argctx import *
 
 from v6d2ctx.context import Context
 
 
 async def yt_audios(ctx: Context, args: list[str]) -> AsyncIterable[YTAudio]:
-    tuples: list[InfoCtx] = []
     assert ctx.guild is not None
-    async for it in entries_effects_for_args(args, ctx.guild.id):
-        tuples.append(it)
-        if len(tuples) >= 5:
-            async for audio in create_ytaudios(ctx, tuples):
-                yield audio
-            tuples.clear()
-    async for audio in create_ytaudios(ctx, tuples):
-        yield audio
+    argctx = ArgCtx(default_effects(ctx.guild.id), args)
+    async with Pool(5) as pool:
+        async for audio in YState(pool, ctx, argctx.sources).iterate():
+            yield audio
diff --git a/v6d3music/html/main.css b/v6d3music/html/main.css
index 9d28873..26b5ce0 100644
--- a/v6d3music/html/main.css
+++ b/v6d3music/html/main.css
@@ -30,15 +30,17 @@ body,
 
 #root-container {
   display: flex;
+  height: 100%;
 }
 
 #root {
   width: auto;
   min-width: min(40em, 100%);
   flex: auto;
+  overflow-y: scroll;
 }
 
 .sidebars {
   width: 100%;
-  background: #111;
+  background: #050505;
 }
diff --git a/v6d3music/processing/pool.py b/v6d3music/processing/pool.py
new file mode 100644
index 0000000..c1e1a5c
--- /dev/null
+++ b/v6d3music/processing/pool.py
@@ -0,0 +1,219 @@
+import asyncio
+from typing import Union
+
+from v6d3music.processing.yprocess import *
+
+__all__ = ('Job', 'Pool', 'JobDescriptor',)
+
+
+class Job:
+    def __init__(self, future: asyncio.Future[None]) -> None:
+        self.future = future
+
+    async def run(self) -> Union['Job', None]:
+        raise NotImplementedError
+
+
+class JobDescriptor:
+    async def run(self) -> Union['JobDescriptor', None]:
+        raise NotImplementedError
+
+    def wrap(self) -> Job:
+        return DescriptorJob(asyncio.Future(), self)
+
+    def at(self, pool: 'Pool') -> 'JDC':
+        return JDC(self, pool)
+
+
+class DescriptorJob(Job):
+    def __init__(self, future: asyncio.Future[None], descriptor: JobDescriptor) -> None:
+        super().__init__(future)
+        self.__descriptor = descriptor
+
+    async def run(self) -> Job | None:
+        next_descriptor = await self.__descriptor.run()
+        if next_descriptor is None:
+            return None
+        else:
+            return DescriptorJob(self.future, next_descriptor)
+
+
+class Worker:
+    def __init__(self) -> None:
+        self.__queue: asyncio.Queue[Job | None] = asyncio.Queue()
+        self.__working = False
+        self.__busy = 0
+
+    def _put_nowait(self, job: Job | None) -> None:
+        self.__queue.put_nowait(job)
+        self.__busy += 1
+
+    async def _handle(self, job: Job) -> None:
+        try:
+            next_job = await job.run()
+        except BaseException as e:
+            job.future.set_exception(e)
+        else:
+            if next_job is None:
+                job.future.set_result(None)
+            else:
+                self._put_nowait(next_job)
+
+    async def _safe_handle(self, job: Job) -> None:
+        try:
+            await self._handle(job)
+        except asyncio.InvalidStateError:
+            pass
+
+    def _on_shutdown(self) -> bool:
+        if self.__queue.empty():
+            self.__working = False
+            return True
+        else:
+            self._put_nowait(None)
+            return False
+
+    async def _on(self, job: Job | None) -> bool:
+        if job is None:
+            return self._on_shutdown()
+        else:
+            await self._handle(job)
+            return False
+
+    async def _step(self) -> bool:
+        job = await self.__queue.get()
+        try:
+            return await self._on(job)
+        finally:
+            self.__busy -= 1
+            self.__queue.task_done()
+
+    async def _work(self) -> None:
+        while True:
+            if await self._step():
+                return
+
+    def _cancel_job(self, job: Job) -> None:
+        try:
+            job.future.set_exception(RuntimeError('task left in the worker after shutdown'))
+        except asyncio.InvalidStateError:
+            pass
+
+    def _cancel_one(self, job: Job | None) -> None:
+        if job is not None:
+            self._cancel_job(job)
+
+    def _cancel_get(self) -> None:
+        job = self.__queue.get_nowait()
+        try:
+            self._cancel_one(job)
+        finally:
+            self.__queue.task_done()
+
+    def _cancel_all(self) -> None:
+        while not self.__queue.empty():
+            self._cancel_get()
+
+    async def _task(self) -> None:
+        await self._work()
+        if self.__working:
+            raise RuntimeError('worker left seemingly running after shutdown')
+        if not self.__queue.empty():
+            raise RuntimeError('worker failed to finish all its jobs')
+
+    def start(self) -> asyncio.Future[None]:
+        if self.__working:
+            raise RuntimeError('starting an already running worker')
+        self.__working = True
+        return asyncio.create_task(self._task())
+
+    def submit(self, job: Job | None) -> None:
+        if not self.__working:
+            raise RuntimeError('submitting to a non-working worker')
+        self._put_nowait(job)
+
+    def working(self) -> bool:
+        return self.__working
+
+    def busy(self) -> int:
+        return self.__busy
+
+
+class Working:
+    def __init__(self, worker: Worker, task: asyncio.Future[None]) -> None:
+        self.__worker = worker
+        self.__task = task
+
+    async def close(self) -> None:
+        self.__worker.submit(None)
+        await self.__task
+
+    def submit(self, job: Job) -> None:
+        self.__worker.submit(job)
+
+    @classmethod
+    def start(cls) -> 'Working':
+        worker = Worker()
+        task = worker.start()
+        return cls(worker, task)
+
+    def working(self) -> bool:
+        return self.__worker.working()
+
+    def busy(self) -> int:
+        return self.__worker.busy()
+
+
+class Pool:
+    def __init__(self, workers: int) -> None:
+        if workers < 1:
+            raise ValueError('non-positive number of workers')
+        self.__workers = workers
+        self.__working = False
+        self.__open = False
+
+    async def __aenter__(self) -> 'Pool':
+        if self.__open:
+            raise RuntimeError('starting an already open pool')
+        if self.__working:
+            raise RuntimeError('starting an already running pool')
+        self.__working = True
+        self.__pool = set(Working.start() for _ in range(self.__workers))
+        self.__open = True
+        return self
+
+    async def __aexit__(self, exc_type, exc_val, exc_tb):
+        if not self.__working:
+            raise RuntimeError('stopping a non-working pool')
+        if not self.__open:
+            raise RuntimeError('stopping a closed pool')
+        self.__open = False
+        for working in self.__pool:
+            await working.close()
+        del self.__pool
+        self.__working = False
+
+    def submit(self, job: Job) -> None:
+        if not self.__working:
+            raise RuntimeError('submitting to a non-working pool')
+        if not self.__open:
+            raise RuntimeError('submitting to a closed pool')
+        min(self.__pool, key=lambda working: working.busy()).submit(job)
+
+    def workers(self) -> int:
+        return self.__workers
+
+
+class JDC:
+    def __init__(self, descriptor: JobDescriptor, pool: Pool) -> None:
+        self.__descriptor = descriptor
+        self.__pool = pool
+
+    async def __aenter__(self) -> 'JDC':
+        job = self.__descriptor.wrap()
+        self.__future = job.future
+        self.__pool.submit(job)
+        return self
+
+    async def __aexit__(self, exc_type, exc_val, exc_tb):
+        await self.__future
diff --git a/v6d3music/utils/argctx.py b/v6d3music/utils/argctx.py
index b6014f3..c8f8019 100644
--- a/v6d3music/utils/argctx.py
+++ b/v6d3music/utils/argctx.py
@@ -1,17 +1,22 @@
-from typing import AsyncIterable, Callable, Any
+from typing import Any, AsyncIterable, Callable
 
 from v6d3music.utils.effects_for_preset import effects_for_preset
 from v6d3music.utils.entries_for_url import entries_for_url
 from v6d3music.utils.options_for_effects import options_for_effects
 from v6d3music.utils.sparq import sparq
 
+__all__ = ('InfoCtx', 'UrlCtx', 'ArgCtx',)
+
 
 class InfoCtx:
-    def __init__(self, info: dict[str, Any], effects: str | None, already_read: int, tor: bool) -> None:
+    def __init__(
+        self, info: dict[str, Any], effects: str | None, already_read: int, tor: bool, ignore: bool
+    ) -> None:
         self.info = info
         self.effects = effects
         self.already_read = already_read
         self.tor = tor
+        self.ignore = ignore
 
 
 class UrlCtx:
@@ -20,14 +25,19 @@ class UrlCtx:
         self.effects = effects
         self.already_read = 0
         self.tor = False
+        self.ignore = False
 
     async def entries(self) -> AsyncIterable[InfoCtx]:
-        async for info in entries_for_url(self.url, self.tor):
-            yield InfoCtx(info, self.effects, self.already_read, self.tor)
+        try:
+            async for info in entries_for_url(self.url, self.tor):
+                yield InfoCtx(info, self.effects, self.already_read, self.tor, self.ignore)
+        except:
+            if not self.ignore:
+                raise
 
 
 class ArgCtx:
-    def __init__(self, default_effects: Callable[[int], str | None], args: list[str], gid: int) -> None:
+    def __init__(self, default_effects: str | None, args: list[str]) -> None:
         self.sources: list[UrlCtx] = []
         while args:
             match args:
@@ -36,7 +46,7 @@ class ArgCtx:
                 case [url, '+', preset, *args]:
                     effects = effects_for_preset(preset)
                 case [url, *args]:
-                    effects = default_effects(gid)
+                    effects = default_effects
                 case _:
                     raise RuntimeError
             ctx = UrlCtx(url, effects)
@@ -56,4 +66,9 @@ class ArgCtx:
                     ctx.tor = True
                 case [*args]:
                     pass
+            match args:
+                case ['ignore', *args]:
+                    ctx.ignore = True
+                case [*args]:
+                    pass
             self.sources.append(ctx)